#include<cmath>
#include<cstdio>

typedef long long ll;
template<class T>
inline void read(T&x)
{
    x=0;bool f=0;char c=getchar();
    while((c<‘0‘||c>‘9‘)&&c!=‘-‘)c=getchar(); if(c==‘-‘)f=1,c=getchar();
    while(c>=‘0‘&&c<=‘9‘){x=x*10+c-‘0‘;c=getchar();}
    x=f?-x:x;
}

const int MAXN(100010),LEN(200010);
const ll INF(0x7fffffffffffffff);
int n,a[MAXN],b[MAXN],l[MAXN];
struct Node{int nd,nx,co;}bot[MAXN<<1];int tot,first[MAXN];
void add(int a,int b,int c){bot[++tot]=(Node){b,first[a],c};first[a]=tot;}
int st[MAXN],pos[MAXN],last[MAXN],tp;bool bf[MAXN],vis[MAXN];
int Ring[LEN],dis[LEN],Rsize;
void DFS(int x,int f)
{
    st[++tp]=x;pos[x]=tp;
    for(int v=first[x];v;v=bot[v].nx)
    if(bot[v].nd!=f)
    {
        if(pos[bot[v].nd])
        {
            if(dis[1])continue;
            for(int i=pos[bot[v].nd];i<=tp;i++)
            {
                Ring[++Rsize]=st[i];bf[st[i]]=1;
                dis[Rsize]=last[st[i]];
            }
            dis[1]=bot[v].co;
        }else 
        {
            last[bot[v].nd]=bot[v].co;
            DFS(bot[v].nd,x);
        }
    }
    --tp;pos[x]=0;
}
void umax(ll &a,ll b){if(a<b)a=b;}
ll max(ll a,ll b){return a>b?a:b;}
ll min(ll a,ll b){return a<b?a:b;}
ll lm[MAXN],Ans,Ans2,all;
void DP(int x)
{
    bf[x]=1;
    for(int v=first[x];v;v=bot[v].nx)
    if(!bf[bot[v].nd])
    {
        DP(bot[v].nd);
        umax(Ans,lm[x]+lm[bot[v].nd]+bot[v].co);
        umax(lm[x],lm[bot[v].nd]+bot[v].co);
    }
}
ll Sv[MAXN],Su[MAXN],Pv[MAXN],Pu[MAXN],Sd[MAXN],Pd[MAXN];
void Get_Ring()
{
    Ring[Rsize+1]=Ring[1];dis[Rsize+1]=dis[1];
    for(int i=1;i<=Rsize;i++)
    {
        Sv[i]=(i!=1)?Sd[i-1]+dis[i]+lm[Ring[i]]:lm[Ring[i]];
        umax(Sv[i],Sv[i-1]);
        Sd[i]=(i!=1)?max(Sd[i-1]+dis[i],lm[Ring[i]]):lm[Ring[i]];
        Su[i]=max(Su[i-1]-dis[i],lm[Ring[i]]);
        all+=dis[i];
    }
    for(int i=Rsize+1;i>1;i--)
    {
        Pv[i]=(i!=Rsize+1)?Pd[i+1]+dis[i+1]+lm[Ring[i]]:lm[Ring[i]];
        umax(Pv[i],Pv[i+1]);
        Pd[i]=(i!=Rsize+1)?max(Pd[i+1]+dis[i+1],lm[Ring[i]]):lm[Ring[i]];
        if(i!=Rsize+1)Pu[i]=max(Pu[i+1]-dis[i+1],lm[Ring[i]]); 
        //以防lm[Ring[1]]被加两次 
    }
    Ans2=INF;
    for(int i=1;i<=Rsize;i++)
        Ans2=min(Ans2,max(max(Sv[i],Pv[i+1]),Su[i]+Pu[i+1]+all-dis[i+1]));
}
int main()
{
//    freopen("C.in","r",stdin);
//    freopen("C.out","w",stdout);
    read(n);
    for(int i=1;i<=n;i++)
    {
        read(a[i]),read(b[i]),read(l[i]);
        add(a[i],b[i],l[i]),add(b[i],a[i],l[i]);
    }
    DFS(1,0);
    for(int i=1;i<=n;i++)if(bf[i])DP(i);
    Get_Ring();
    umax(Ans,Ans2);
    printf("%.1lf",(Ans+0.05)/2.0);
    return 0;
}